Dual 177 Lu-Prostate-Specific Membrane Antigen and 177 Lu-DOTATATE Therapy in Metastatic Castration-Resistant Prostate Cancer With Neuroendocrine Differentiation.

ABSTRACT: We present an 87-year-old man diagnosed with prostate cancer and neuroendocrine differentiation, posttherapy results to consecutive 177 Lu-prostate-specific membrane antigen and 177 Lu-DOTATATE. Despite hormonal therapy and chemoradiotherapy, the patient progressed rapidly, and multiple liver and bone metastases showed regression after 177 Lu-prostate-specific membrane antigen and 177 Lu-DOTATATE treatment. Prostate cancer with neuroendocrine differentiation is resistant to treatments; however, treatment with the combination of 177 Lu-DOTATATE therapy may be promising.

The Contribution of 68Ga-FAPI-04 PET/CT to Staging and Prognosis in Gastric Cancer.

AIM: This study aimed to compare the diagnostic capabilities of 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT imaging in staging gastric carcinoma, exploring the impact of 68Ga-FAPI-04 PET/CT on treatment planning and its prognostic significance. METHODS: The research included 31 patients undergoing staging for gastric cancer, who received both 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT scans. We compared the SUVmax and SUVmean of the primary tumor and lymph nodes, the count of organ metastases, tumor-to-background ratios, and overall staging accuracy. Additionally, the study evaluated radiological progression-free survival and overall survival rates. RESULTS: The 68Ga-FAPI-04 PET/CT demonstrated superior efficacy in identifying the primary tumor compared with 18F-FDG PET/CT, particularly in cases of poorly cohesive, signet-ring cell, and mucinous subtypes, with detection rates of 96.7% versus 77.4% (P = 0.006 and P = 0.008, respectively). Analysis of lymph nodes showed a significantly higher detection of positive nodes with 68Ga-FAPI-04 (P = 0.026), although no significant differences were observed in SUVmax and tumor-to-background ratio on a patient basis (P > 0.05). SUVmax and tumor-to-background ratios for peritoneal involvement were notably higher with 68Ga-FAPI-04 PET/CT compared with 18F-FDG PET/CT (P = 0.04 for both). No significant differences were found in the detection of organ metastases and disease stage between the 2 imaging modalities (P > 0.05). Primary tumor uptake did not significantly impact radiological progression-free survival or overall survival in either modality. CONCLUSION: 68Ga-FAPI-04 PET/CT imaging surpasses 18F-FDG PET/CT in detecting the primary tumor, especially in poorly cohesive and signet-ring cell gastric cancer types, and offers improved accuracy in disease staging. This indicates its potential to enhance treatment management and prognostic assessment in gastric cancer patients.

Contribution of 68 Ga-DOTA-FAPI-04 PET/CT to Prostate Cancer Imaging : Complementary Role in PSMA-Negative Cases.

PURPOSE: Prostate-specific membrane antigen (PSMA)-targeted PET/CT is a well-established imaging method in prostate cancer (PC) for both staging and restaging, and also for theranostic applications. An alternative imaging method is crucial for 15% PSMA-negative cases. We aimed to investigate the contribution of 68 Ga-DOTA-FAPI-04 PET/CT to PC imaging. PATIENTS AND METHODS: Thirty-six patients diagnosed with PC were included. Patients underwent both 68 Ga-PSMA PET/CT and 68 Ga-DOTA-FAPI-04 PET/CT imaging within 1 week. In staging group, primary tumor uptake values were compared, and also correlations were done with histopathological findings, MRI findings, and total PSA levels. In biochemical recurrence group, the uptake values in prostatic region and metastases were evaluated to define the local recurrence or metastatic disease. RESULTS: In staging group, PSMA PET showed increased uptake in the primary lesion area in 14/27 (52%) patients, whereas 20/27 (74%) patients were positive in FAPI-04 PET. FAPI-04 positivity was found to be quite high, such as 54%, in PSMA-negative patients. A significant difference was observed between ISUP grade 1-3 patients and ISUP grade 4-5 patients in FAPI-04 PET ( P = 0.03). Local recurrence was detected in 3 patients, pelvic lymph node metastasis in 1 patient, and sacrum metastasis in 1 patient in biochemical recurrence group, and all of the lesions had more intense uptake in PSMA PET than FAPI-04 PET. CONCLUSIONS: FAPI PET imaging seems to have a potential to contribute PSMA PET imaging with FAPI positivity in more than half of PSMA-negative cases. Also, FAPI-targeted radionuclide therapy may be a promising method in patients resistant to PSMA-targeted therapy.

Increased FDG Uptake in Skin Rashes Caused by EGFR Inhibitors.

ABSTRACT: Most patients treated with epidermal growth factor receptor inhibitors develop cutaneous advance effects. The extent and severity of treatment-related skin rashes are associated with good treatment response and prognosis. Herein, we presented increased uptake of the 18F-FDG in skin rashes after treatment with epidermal growth factor receptor inhibitors in 2 patients diagnosed with metastatic colorectal cancer.

Role of 68 Ga-FAPI PET/CT in Screening Malignancy of Familial Adenomatous Polyposis.

ABSTRACT: A 57-year-old man with familial adenomatous polyposis (FAP) and newly diagnosed colonic adenocarcinoma was referred to 18 F-FDG PET/CT for staging and 68 Ga-FAPI-04 PET/CT for ongoing trial. 18 F-FDG PET/CT showed equal intense 18 F-FDG uptake in the tumor and multiple hypermetabolic polypoid lesions in the entire colorectum. 68 Ga-FAPI-04 PET/CT showed intense 68 Ga-FAPI-04 uptake only at the colonic tumor, without uptake at polypoid lesions.

Chronic Gastritis Mimicking Malignancy on 68 Ga-FAPI-04 PET/CT.

ABSTRACT: We present 2 patients mimicking malignancy with intense gastric 68 Ga-FAPI-04 uptake on PET/CT. Both patients showed low to moderate 18 F-FDG uptake. Histopathology revealed chronic active gastritis. Chronic gastritis may resemble gastric malignancies by showing false-positive 68 Ga-FAPI-04 uptake.

Findings of I-131 SPECT/CT, 18F-FDG, and 68Ga-FAPI-04 PET/CT Imaging in a Patient Treated with Radioiodine Therapy for Metastatic Papillary Thyroid Carcinoma.

A 50-year-old man undergone total thyroidectomy and histopathology revealed papillary thyroid carcinoma with a tumor size of 4.5 cm. The patient was referred to a nuclear medicine clinic for radioiodine therapy. Since the thyroglobulin level before the treatment was 495 ug/L, low-dose (185 MBq) I-131 scan was performed. In addition to multiple liver metastases, bone metastases were detected in the sacrum and right 7th rib in I-131 whole body scanning and single photon emission computed tomography/computed tomography (CT) imaging at the time of initial staging. We present a case of multiple metastatic papillary thyroid carcinoma whose radioiodine treatment response and clinical outcome were evaluated with 18F-fluorodeoxyglucose and Gallium-68 FAPI-04 positron emission tomography/CT.

Pneumonia with Intense 68Ga-FAPI Uptake Mimicking Metastasis on 68Ga-FAPI PET/CT in a Patient with Rectal Cancer.

A 70-year-old man with newly diagnosed rectum adenocarcinoma was referred to 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for staging, and 68Ga-fibroblast activation protein inhibitor (FAPI)-04 PET/CT for ongoing trial. Both 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT showed intense uptake in the primary rectal tumor, and also in nodular areas in the right lung. Due to intense 68Ga-FAPI-04 and 18F-FDG uptake, the lung lesions were considered as metastases. However the lesions were reduced in size on CT after 20 days antibiotherapy and diagnosed as pneumonia.

68Ga-FAPI-04 PET/CT Findings in Patients with Liver Cirrhosis.

Fibroblast activation protein (FAP) is expressed as a pro-inflammatory agent from fibrous tissue in liver cirrhosis and in the tumor microenvironment. Cirrhosis is the last stage of any chronic liver disease, and the natural course of cirrhosis is the progression from the asymptomatic phase to the symptomatic decompensated phase with the development of ascites. Although various clinical features suggest cirrhosis in patients with chronic liver disease, non-invasive methods should follow the clinical approach before a definitive diagnosis. Herein, we present three cases of liver cirrhosis with fibroblast activation protein inhibitor (FAPI) uptake to demonstrate the usefulness of 68Ga-FAPI-04 positron emission tomography/computed tomography (PET/CT) scan in cirrhosis.

Testicular Metastasis of Jejunal Neuroendocrine Tumor on 68Ga-DOTATATE PET/CT.

Neuroendocrine tumors are slow-growing tumors originating from neuroendocrine cells and capable of metastasis. Most of them are found in the gastrointestinal tract; however, they can also be rarely seen in other organs. Testicular neuroendocrine tumors account for less than 1% of all testicular neoplasms. They may present as primary testicular or secondary tumors from extratesticular sources. Jejunal neuroendocrine tumor metastasis to the testis is extremely rare. We present the case of a 61-year-old man with a jejunal neuroendocrine tumor and metastases to bilateral testicles revealed on Gallium-68-DOTATATE positron emission tomography/computed tomography.

68 Ga-FAPI-04 PET/CT in Selected Breast Cancer Patients With Low FDG Affinity : A Head-to-Head Comparative Study.

PURPOSE: In this prospective study, PET findings of 18 F-FDG PET/CT in breast cancer staging were compared with 68 Ga-FAP inhibitor (FAPI) 04 PET/CT findings in selected cases with relatively low 18 F-FDG uptake in the primary tumor or with suspected nodal or distant metastases. PATIENTS AND METHODS: Twenty-four women with a median age of 45 years (range, 36-67 years) who underwent initial staging 18 F-FDG PET/CT for breast cancer underwent 68 Ga-FAPI-04 PET/CT imaging within the same week. SUV max and quantities of primary tumors and locoregional and distant metastatic lesions were recorded from both images, and these data were compared statistically. RESULTS: The histological subtypes of primary tumors were 11 invasive lobular, 8 invasive ductal, and 5 mucinous subtypes. More intense 68 Ga-FAPI-04 uptake (mean, 17.1 ± 7.9; 7.4-38.5) was detected in all primary tumoral lesions compared with 18 F-FDG (mean, 6.3 ± 3.9; 1.5-20.5) ( P = <0.001, Z = 4.107). Additional lesions showing 68 Ga-FAPI-04 uptake in the breast were detected in 29.2% (n = 7) of patients. In 8.3% (n = 2) of the patients, the primary lesion showed only 68 Ga-FAPI-04 uptake. In 68 Ga-FAPI-04 PET/CT, 25% (n = 6) of the patients showed more lymph node involvement and more intense uptake in the ipsilateral axilla. In addition, infraclavicular (level 3) lymph nodes in 4 patients (16.7%), supraclavicular lymph nodes in 1 patient, and internal mammary lymph nodes in 1 patient were detected only on 68 Ga-FAPI-04 PET/CT. In a patient with lung and bone metastases, 68 Ga-FAPI-04 uptake was higher, and the lung nodule showed only 68 Ga-FAPI-04 uptake. CONCLUSIONS: In selected low-FDG-affinity breast cancer patients, 68 Ga-FAPI-04 PET/CT showed the primary tumor with higher sensitivity and higher SUV max values compared with 18 F-FDG PET/CT. In addition, it is believed that this method may contribute to the management of patients' treatment by increasing the nodal stage.

The potential role of 68Ga-FAPI-04 PET/CT for screening malignancy in suspected colonic lesions.

AIM: Benign colonic lesions like tubular adenoma may show intense uptake on F-18-FDG PET/CT and can be mistaken for malignancy. In this study, we evaluated the role of 68Ga-FAPI-04 PET/CT for discriminating the benign and malignant colonic lesions. METHODS: Forty patients with diagnosis of colorectal cancer who had undergone 18F-FDG-PET/CT and 68Ga-FAPI-04 PET/CT for initial staging were retrospectively analyzed. The unexpected foci of uptake in colon on 18F-FDG PET/CT were compared with 68Ga-FAPI-04 PET/CT with lesion and background SUVmax. RESULTS: The primary colorectal lesion SUVmax on both PET/CTs was similar. A total of 9 incidental colon lesions in 7 patients were detected showing intense 18F-FDG uptake and no 68Ga-FAPI-04 uptake. All of the lesions were consistent with tubular adenoma histopathologically. CONCLUSION: 68Ga-FAPI PET/CT may have a crucial role for discrimination of benign and malignant colonic lesions and avoid the unnecessary interventions and extended surgeries in patients with colorectal cancer.

The roles of 68 Ga-PSMA PET/CT and 18 F-FDG PET/CT imaging in patients with triple-negative breast cancer and the association of tissue PSMA and claudin 1, 4, and 7 levels with PET findings.

AIM: Aim of study is to compare the results of Gallium-68-prostate-specific membrane antigen ( 68 Ga-PSMA) and 18 F-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography(PET)/computed tomography (CT), to evaluate the correlation between PET findings and the level of PSMA, Claudin (Clau) 1, 4, and 7 receptors obtained by immunohistochemical (IHC) analysis, and to determine potential predictive and prognostic values in TNBC. METHODS: Forty-seven lesions of 42 subjects diagnosed TNBC both underwent PET/CT scan for preoperative staging/restaging were prospectively included study. PSMA, Clau 1, 4, and 7 expressions were IHC evaluated from the biopsy samples of the primary tumor (PT). Maximum standardized uptake value(SUV max) of the PT, lymph node, and distant organ metastases (DOMs) on 18 F-FDG and 68 Ga-PSMA PET/CT were compared with PSMA, Clau 1, 4, and 7 receptor expressions. RESULTS: IHC analyses on 29 BC lesions to demonstrate Clau expression showed 86% (25/29) Clau 1, 86% (25/29) Clau 4, 45% (13/29) Clau 7, and 48% (14/29) PSMA-positive. The mean DOM (SUVmax) was 15.5 ± 11.6 for 18 F-FDG and 6.0 ± 2.9 for 68 Ga-PSMA. Axial diameter of BC PT had a significant positive correlation with 18 F-FDG SUVmax, 68 Ga-PSMA SUVmax, and PSMA scores. BC lesions 68 Ga-PSMA SUVmax had a significant negative correlation with the Ki-67 index. Axial diameter of the primary tumor had significant negative correlation with Clau 7 scores ( r = -0.409, P = 0.034). Absence of Clau 1 expression found to significantly increase the rate of DOM (100% vs. 28%) ( P = 0.014). All patients with axillary lymph node (ALN) metastases ( n = 17, 100%) exhibited Clau 4 positivity ( P = 0.021). The presence of PSMA expression observed to significantly increase the rate of ALN metastases (64.7% vs. 25%) ( P = 0.035). CONCLUSION: Confirming PSMA expression with PET imaging would be significant as PSMA, a theranostic agent, may be a considerable potential agent for radionuclide treatment strategies, in addition to its additional diagnostic contribution to FDG, especially in patients with metastatic TNBC, which is an aggressive, heterogeneous disease.

Contribution of 18F-FDG PET/CT imaging in the diagnosis and management of HIV-positive patients.

INTRODUCTION AND OBJECTIVES: The human immunodeficiency virus [HIV] is a lentevirus, primarily infects certain cells of the immune system, thereby greatly weakens the body's own defenses against diseases. This study was aimed to explore the value and significance of 18F-FDG PET/CT in the assessment of patients with HIV infection and to examine the presence of quantitative alterations in 18F-FDG uptake among patients with HIV-related infections or malignant diseases in HIV-positive patients. PATIENTS AND METHODS: Forty patients with HIV infection were scanned on PET/CT system. The data were registered according to immune status, antiretroviral therapy, and definitive diagnosis. All pathologic lesions and disease related areas were described, 18F-FDG uptake patterns were evaluated. Semiquantitative analysis of 18F-FDG uptake was performed and SUVmax were calculated. RESULTS: Twenty-eight patients [70%] were diagnosed with HIV-related infection or malignant diseases. The sensitivity of PET/CT was shown to be 100% and the specificity 92% for concomitant diseases requiring additional treatment to antiretroviral therapy. The SUVmax and CD4 counts were not statistically different between HIV-related reactive lymphadenopathy, HIV-related malignancy, and HIV-related infections. CONCLUSIONS: The pattern of distribution of nodal/extranodal uptake on 18F-FDG PET/CT may facilitate distinction between HIV-related generalized lymphadenopathies, HIV-related opportunistic infections, and malignancies. In this context, 18F-FDG PET/CT should be preferred for routine use in the management of patients infected with HIV.

Intense 68Ga-DOTA-FAPI-04 Uptake in Diffuse Sclerotic Skeletal Metastases of Gastric Cancer.

ABSTRACT: Diffuse sclerotic metastases of the bone as initial presentation at gastric carcinoma are very rare. We present a 48-year-old man who was examined for pancytopenia and diagnosed with gastric cancer. 18F-FDG PET/CT showed moderate uptake in the primary gastric tumor and mild uptake in diffuse sclerotic metastatic lesions in the bone matrix, whereas 68Ga-DOTA-FAPI-04 showed mild uptake in the gastric lesion and intense uptake at the whole skeleton.

Vas Deferens and Inguinal Canal Metastasis of Prostate Cancer Revealed by 68 Ga-Prostate-Specific Membrane Antigen PET/CT.

ABSTRACT: A 71-year-old man with prostate adenocarcinoma underwent 68 Ga-prostate-specific membrane antigen (PSMA) PET/CT for staging. 68 Ga-PSMA PET/CT showed the primary lesion along with bladder, rectum, bilateral seminal vesicle invasion, and metastatic pelvic lymph nodes with intense 68 Ga-PSMA uptake. Also, PET/CT showed rarely seen bilateral vas deferens invasion and metastasis to the inguinal canal. These rare metastases may be indicative of poor biological behavior and prognosis.

68 Ga-DOTATATE Uptake in Well-Differentiated Neuroendocrine Tumor of the External Auditory Canal.

ABSTRACT: A 38-year-old woman presented with a 4-month history of left-sided otalgia and otorrhea. Otoscopy revealed a mass in the left external auditory canal causing obliteration. A biopsy was taken, and the diagnosis was consistent with a well-differentiated neuroendocrine tumor. The patient was referred to our department for staging with 68 Ga-DOTATATE PET/CT. Increased radiopharmaceutical uptake was observed in the primary tumor and metastatic lymph nodes.

Intense 68 Ga-PSMA Uptake in Neurofibroma Mimicking Cutaneous Metastases in a Patient With Prostate Cancer.

ABSTRACT: Prostate cancer is the most common cancer in men. 68 Ga-PSMA PET/CT is frequently used in staging and restaging prostate cancer; it is important to keep in mind the causes of false-positives when evaluating imaging. We present findings of 68 Ga-PSMA PET/CT and histopathological features of a 68-year-old prostate cancer man with neurofibroma. 68 Ga-PSMA PET/CT showed intense 68 Ga-PSMA uptake in neurofibroma.

Gallbladder Metastasis From Renal Cell Carcinoma Revealed With 18 F-FDG PET/CT.

ABSTRACT: Gallbladder metastasis from renal cell carcinoma is a rare condition. To our knowledge, only 1 case has been reported with 18 F-FDG PET/CT findings. Herein, we report the case of a 53-year-old man with renal cell carcinoma, having gallbladder metastasis revealed with restaging 18 F-FDG PET/CT.

Mild 68Ga PSMA-11 Uptake in Incidental Pituitary Adenoma.

A 76-year-old man with metastatic prostate cancer was referred to 68Ga prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) for restaging. A consecutive 18F-fluorodeoxyglucose (FDG) PET/CT was performed due to the history of lung cancer in the left lung treated with stereotactic radiotherapy. Intense 18F-FDG uptake was detected in the pituitary gland despite the mild uptake of 68Ga PSMA. Contrast-enhanced magnetic resonance imaging confirmed pituitary adenoma.